What is the lifecycle of an element in Flutter?

The element has three main states:

1. Creation: The element is created in the element tree, usually through the widget's createElement() during its inflating.
2. Active: The element is in the tree, has an associated rendering object (or is a proxy element), and can be displayed on the screen. This is the primary state.
3. Inactive: The element has been removed from the active tree (for example, the parent widget chose not to include it). It moves to the list of inactive elements, where it can be reused or eventually garbage collected.

Key lifecycle methods:

• mount(): Called when the element is first added to the tree.
• activate(): Called when an inactive element becomes active again.
• deactivate(): Called when an element becomes inactive.
• unmount(): Called when the element is finally removed from the tree and will no longer be used.

When the configuration changes (for example, updating a widget), the Element may call update() to update its associated widget and possibly its child element(s).

A simplified flow example:

// Creation
Widget widgetConfig = MyWidget();
Element element = widgetConfig.createElement();
element.mount(parent, newSlot);

// ... Element work ...

// Updating configuration
Widget newWidgetConfig = MyNewWidget();
element.update(newWidgetConfig); // Element compares widgets and updates

// ... Element work ...

// Deactivation (for example, parent widget no longer includes it)
element.deactivate();

// ... Element can be reactivated or discarded ...

// Unmounting (discarding)
element.unmount();